Advanced BLDC Motor Drive and Control. Giovanni Tomasello Applications Engineer

Transcription

1 Advanced BLDC Motor Drive and Control Giovanni Tomasello Applications Engineer

2 3-Phase BLDC Motor-Control Block Diagram HV Only PFC Controllers (L49xx) Rectifiers (STTHxx, STPSxx) Power MOSFETs (Mdmesh M2, M5 600V-650V) HV and LV IGBT (TFS 600V V) IPM (SLLIMM ) Power MOSFETs (HV and LV) SYSTEM IN PACKAGE (SiP): STSPIN32 (up to 45V) PFC Gate driver Inverter stage Tools (HW & SW) Gate driver Gate driver Motor M Auxiliary power supply Control unit Current sensing Sensor and signal conditioning Power Management VIPERxx, LDO, DC-DC Op. Amp. and comparators Microcontrollers 8-bit / 32-bit Gate Drivers L638x, L639x, L649x (1), STGAPxx

3 Electric Motor: Classification Sinusoidal Permanent Magnet (PMSM) Internal mounted PM Higher efficiency and/or reliability Synchronous Wound field Surface mounted PM Trapezoidal (BLDC) PM AC Variable reluctance Switched reluctance Electric motors DC (brushed) Asynchronous (ACIM) Squirrel cage Stepper Wound rotor Universal PMSM: 3-phase permanent magnet synchronous motor ACIM: 3-phase induction motor Limited computation needs Driving method well-known, mastered by customer Light ecosystem Basic ADC/PWM requirement Computation intensive Complex driving, requires specific knowledge and/or support Complete ecosystem necessary Requires 3-phase timer + sync d ADC

4 Permanent Magnet Synchronous Motor (PMSM) Stator is the same as AC IM: three phase windings Rotor houses permanent magnets PMSM and BLDC Motors on the surface Surface Mounted (SM) PMSM Buried within the rotor Internal (I) PMSM Rotation induces sinusoidal Back Electro-Motive Force (BEMF) in motor phases Gives best performances (torque steadiness) when driven by sinusoidal phase current Permanent Magnet BrushLess DC motors (BLDC) Like PMSM - and despite of their name - require alternating stator current Like in PMSM, rotor houses permanent magnets, usually glued on the surface Like PMSM, stator excitation frequency matches rotor electrical speed Unlike PMSM, rotor spinning induced trapezoidal shaped Back Electro- Motive Force (Bemf) Gives best performances (torque steadiness) when driven by rectangularshaped currents Optimum current shape Optimum current shape Typical b-emf shape Typical B-emf shape

5 Operating voltage from 8V to 45V 3-phase gate driver for high performances 600mA current capability Real-time programmable over current Integrated bootstrap diodes Cross conduction, under-voltage and temperature protections 32-bit STM32F0 MCU with ARM Cortex M0 Core STM32F031x6x7 48MHz, 4-Kb SRAM and 32-Kb Flash 12-bit ADC 1 to 3 shunts FOC supported Communication interfaces I2C, UART and SPI Complete Development Ecosystem available 4x Operational Amplifiers and a Comparator STSPIN32F0 Technical Details On-chip generated supplies for MCU driver and external circuitry 3.3V DC/DC buck regulator Input voltage up to 45V 12V LDO linear regulator UVLO protection on all power supply voltages Embedded Over-Temperature Protection Package : VFQFPN 7 x 7 x L

6 STSPIN32F0 Application Example

7 Making Your Designs Easier To support STSPIN32F0, a comprehensive set of design tools is available, including: Reference Code STSPIN32F0 evaluation board Description Three-phase brushless DC motor driver evaluation board STEVAL-SPIN3201 UM2154 STSW-SPIN3201 UM2152 STSW-STM32100 Input voltage from 8 to 45 V Output current up to 15 Arms Power stage based on STD140N6F7 MOSFETs Sensored or sensorless field-oriented control algorithm with 3-shunt sensing User manual for STEVAL-SPIN3201: advanced BLDC controller with embedded STM32 MCU evaluation board Firmware example for field oriented motor control (FOC) User manual for Getting started with the STSPIN32F0 FOC firmware example STSW-SPIN3201 Library: STM32 PMSM FOC Software Development Kit

8 Why FOC? Best energy efficiency even during transient operation. Responsive speed control to load variations. Decoupled control of both electromagnetic torque and flux. Acoustical noise reduction due to sinusoidal waveforms. Active electrical brake and energy reversal. ąß Clark Park Park -1 Clark -1 Independent control of flux and torque

9 FOC Single Motor For Budgetary Applications Target applications: All those applications where: Dynamic performance requirements are moderate Quietness of sinusoidal current control (vs six steps drive) is valuable Extended speed range is required Particularly suitable for pumps, fans and compressors Current Current DW Spray & drain pumps WM Drain pump Fridge compressor

10 FOC Single Or Dual Motor For Higher Performance Target applications: Wide range from home appliances to robotics, where: Accurate and quick regulation of motor speed and/or torque is required (e.g. in torque load transient or target speed abrupt variations) CPU load granted to motor control must be low, due to other duties Fitness, wellness and healthcare Games Industrial motor drives And much much more Home appliances Power tools Escalators and elevators

11 t PMSM FOC Overview Field Oriented Control: stator currents (Field) are controlled in amplitude and phase (Orientation) with respect to rotor flux current sensing is mandatory (3shunt/1shunt/ICS) speed / position sensing is mandatory (encoder/hall/sensorless alg) current controllers needed (PI/D,FF) not easy high frequency sinusoidal references + stiff amplitude modulation.. reference frame transformation (Clarke / Park) allows to simplify the problem: el el Φ s Φ r T e maximized if

12 PMSM FOC Overview: Reference Frame Transformations Clarke: transforms i a,i b,i c (120 ) to i α,i β (90 ); (consider that ia+ib+ic=0); i i as i a i i i as 2i α i β b ic i bs Park: currents i α,i β, transformed on a reference frame rotating with their frequency, become DC currents i q,i d (90 )! 3 i i q i α i β qs r r id i ds i i a cos i sin i r sin cos r PI regulators now work efficiently in a DC domain; their DC outputs, voltage reference v q,v d are handled by the Reverse Park -> v α,v β AC domain v q v d v v v qs v cos v qs r r ds sin v sin ds r cos r v α v β

13 ST SLLIMM IPM Single PMSM FOC Block Diagram Power Bridge Motor SMART SHUTDOWN-BKIN, DC V - TEMP Gate drivers Current sensors: 3shunt/1shunt/ ICS Speed sensors: Sensorless, Hall, Encoder ω r*,t Speed Control RAMP GENERATOR MTPA & FLUX WEAKENING CONTROLLER Te* ω r * PID + i q * i d * FOC Current Control PID PID v qs v ds i qd REVERSE PARK + circle limitation θ r el PARK v αβ i αβ Space Vector PWM v abc CLARKE i abc - PHASE CURRENTS FEEDBACK θ r el ω r DC domain AC domain ROTOR SPEED/POSITION FEEDBACK

14 Dual PMSM FOC Block Diagram Gate drivers Power bridge1 Motor1 ω r* 1 ω r* 2 v a,b,c BKIN Current sensors: 3shunt/1shunt/ICS Speed sensors: Sensorless, Hall, Encoder BKIN Motor2 v a,b,c Gate drivers Current sensors: 3shunt/1shunt/ICS Power bridge2 Speed sensors: Sensorless, Hall, Encoder

15 Motor Current Sensing Why? The purpose of field oriented control is to regulate the motor phase currents. To do this the three motor phase current need to be measured. Measured motor phase current Ia, Ib, Ic FOC Current reference Voltage command PWM duty

16 Current Sensing Topologies To measure the motor phase currents a conditioning network is required. The STM32 FOC SDK supports three current sensing network Insulated current sensor (ICS) Three shunts Single shunt Insulated current sesor (ICS) Three shunts Single shunt Best quality Cost optimized

17 Current Sensing Topologies According to the HW the current sensing topology can be selected in the power stage scetion of Workbench Insulated current sesor (ICS) Three shunts Single shunt

18 STM32 PMSM FOC SDK v4.3 STSW-STM includes the PMSM FOC FW library, ST MC Workbench (GUI) and Motor Profiler (GUI), allowing the user to evaluate ST products in applications driving single or dual Field Oriented Control of 3-phase Permanent Magnet motors (PMSM), featuring STM32F3xx, STM32F4xx, STM32F0xx, STM32F1xx, STM32F2xx STM32 PMSM FOC SDK v4.3

19 Feature Set According To The Micro Motor Control Firmware Library STM32F4xx, STM32F3xx STM32F103x HD/XL, STM32F2xx STM32F103x LD/MD STM32F100x, STM32F0xx 1shunt Flux Weakening IPMSM MTPA 3shunt F0 supported Digital PFC (3) New Motor Profiler Feed Forward Sensor-less (STO + PLL) Sensor-less (STO + Cordic) FreeRTOS Dual FOC HFI (1) Encoder Hall sensors Startup on-the-fly ICS Max FOC (2) F103 ~23kHz F2xx ~40kHz Max FOC (2) F3xx ~ 30kHz F4xx ~50kHz ST MC Workbench support USART based com protocol add-on Max FOC (2) F100 ~11kHz F0xx ~12kHz Max FOC (2) ~23kHz Max Dual FOC (2) F103 ~20kHz F2xx ~36kHz Max Dual FOC (2) F3xx ~27kHz F4xx~45kHz Foc rate = PWM freq Execution rate (1) High Frequency Injection (2) Max FOC estimated in sensorless mode (3) STM32F103xC/D/E/F/G and STM32F303xB/C

20 STM32 FOC SDK Lab Session Tools: configuration with PC SW STMCWB, Motor Profiler, IDEs

21 Motor Control SDK Workflow Setup the HW Use Motor specs or Identify the motor with Motor Profiler Debug and Real time monitoring Finalize the project with Workbench

22 Motor Control SDK Workflow 1/4 First step Setup the Hardware, according the user's targets it is possible to choose the more suitable HW among the different ST ready-to-start evaluation boards. Setup them according the specification stated in each related user manual. Connect the board together (if required), power supply and plug your motor.

23 MC Connector Flexible MC Platform Full set of control board featuring all ST MCUs Full set of Power board featuring Power Transistor, IPM, MC Driver ICs. STM32XX-EVAL Control board STEVAL-XX Power board NUCLEO-XX Control board X-NUCLEO-IHM09M1 Connector Adapter +

24 Motor Control SDK Workflow 2/4 When the hardware is ready, if the user does not know the motor parameters, he can identify the motor. How? Using the Motor Profiler!!

25 Motor Profiler

26 ST MC Workbench Motor section contains: Motor parameters Motor sensor parameters Set Up Motor Parameters For a custom project, the user can set all the parameters.

27 Setup Motor Profiler Select Boards button and a list of supported boards will be shown. The Motor Profiler feature can be used only in the systems listed there.

28 Parameters set by the user: Setup Motor Profiler Motor pole pairs (Mandatory) Maximum application speed Not mandatory, if not selected, the Motor Profiler will try to reach the maximum allowed speed. Maximum Peak Current The maximum peak current delivered to the motor Expected bus voltage provided to the system. Selecting the kind of Motor Surface Permanent Magnet motor SM-PMSM or Internal Permanent Magnet motor I-PMSM In this last case is necessary to provide also the Ld/Lq ratio as input. SM-PMSM I-PMSM

29 Connect the HW chosen to the PC Click on the Connect button If the communication has succeed Click on the Profile button Setup Motor Profiler

30 Run Motor Profiler Procedure will end in about 60 seconds. Motor stopped Rs measurement Ls measurement Current regulators set-up Open loop Ke measurement Sensorless state observer set-up Switch over Closed loop Friction coefficient measurement Moment of inertia measurement Speed regulator set-up

31 Motor Profiler Complete At the end of the procedure, the measured parameters will be shown on a dedicated window. It is possible to import them on the workbench project and save them for later use.

32 Motor Identified: user can start and stop the motor thorough Start and Stop button. Motor Identified it is possible to create ST MC Workbench new project with the profiled motor,clicking New Project, in the Motor section the user can find

33 Motor Profiler The Motor Profiler algorithm is intended to be used for a fast evaluation of the ST three phase motor control solution (PMSM) Motor Profiler can be used only using compatible ST evaluation boards. Choosing the best ST HW according to the motor characteristics. The measurement precision can not be like when an instrumentation is used. Motor Profiler measurement cannot become significant for some motors, please see the limits reported in the software tool.

34 How To Manually Measure Motor Parameters

35 PMSM - Motor Parameters STMCWB Motor section contains: Electrical motor parameters Motor sensor parameters

36 PMSM - Electrical Motor Parameters Select either Internal PMSM or Surface Mounted PMSM according to the magnetic structure of your motor If you don t have this information you need to measure both Ld and Lq inductance for verifying it IF 2*(Lq-Ld)/(Ld+Lq) <15% SM-PMSM See next slides for learning how to measure motor inductances

37 PMSM Pole Pairs Number Usually, it s provided by motor supplier In case it s not or if you d like to double check it Connect a DC power supply between two (of the three) motor phases and provide up to 5% of the expected nominal DC bus voltage (you may also set current protection to nominal motor current) Rotate the motor with hands (you should notice some resistance) The number of rotor stable positions in one mechanical turn represents the number of pole pairs + - DC voltage source

38 How To Measure Motor Inductance 1/3 In case of SM-PMSM, the phase inductance does not depends on rotor position. In this case Ls notation is also utilized If you have a RLC meter Connect it phase-to-phase and measure series R and L at 100Hz (make sure rotor doesn t move) Repeat 4*number of pole pairs times: Turn the rotor by 360/(4*number of pole pairs) mechanical degrees, + - Wait for new measurements to get stable Read new measurement RLC meter f = 100Hz IF 2*(Lq-Ld)/(Ld+Lq) <15% SM - PMSM In this case, in the Workbench you can use for Rs and Ls half of the values read on the instrument STMCWB requires phase to neutral value with RLC meter

39 How To Measure Motor Inductance 1/3 IF 2*(max(L)-min(L))/(max(L)+min(L)) > 15% I - PMSM In the Workbench you can set Ld equal to minimum measured value divided by 2 (STMCWB requires phase to neutral value), set Lq equal to maximum measured value divided by 2 Set Rs equal to average measured resistance divided by two + - RLC meter f = 100Hz with RLC meter

40 How To Measure Motor Inductance 2/3 If you don t have a RLC meter For Rs, measure the DC stator resistance phase-to-phase and divide it by two Once measured Rs, it s necessary to measure L/R time constant between two motor phases. Connect DC voltage between two motor phases Connect oscilloscope Increase the voltage up to the value where the current equals the nominal one, rotor with align Don t move rotor any more Disable current protection of DC voltage source Unplug one terminal of the voltage source cable without switching it off Plug the voltage source rapidly and monitor on the scope the voltage and current waveform The measurement is good if the voltage is a nice step and the current increase like I * (1-e- t *L/R) Measure the time required to current waveform to rise up to 63% This time is Ld/Rs constant. Multiply it by Rs and you ll get Ld value I V V 0.63*I τ = L/R + - DC voltage source I without RLC meter

41 How To Measure Motor Inductance 3/3 Once measured Rs, it s necessary to measure Lq/Rs time constant between two motor phases. Connect DC voltage between two motor phases Connect oscilloscope Increase the voltage up to the value where the current equals the nominal one, rotor with align Lock the rotor in this position (so that it can not move anymore) Change DC voltage source connections as shown in the second figure Unplug one terminal of the voltage source cable without switching it off Plug the voltage source rapidly and monitor on the scope the voltage and current waveform The measurement is good if the voltage is a step and the current increase like I * (1-e - t *L/R ) Measure the time required to current waveform to rise up to 63% This time is Lq/Rs constant. Multiply it by 2Rs/3 and you ll get Lq value DC voltage source DC voltage source 0.63*I - V + V I τ = L/R + - I without RLC meter

42 How To Measure Bemf 1/2 The B-emf constant represents the proportionality constant between the mechanical motor speed and the amplitude of the B-emf induced into motor phases: To measure K e, usually is sufficient to turn the motor with your hands (or using drill or another motor mechanically coupled) and look with an oscilloscope to phase-to-phase induced voltage (V Bemf ) V Bemf = K e ω mec + - If you have no access to the rotor (e.g. in compressor applications) see next slide Measure VBemf frequency (FBemf) and peak-to-peak amplitude (VBemf A) Compute Ke in Vrms / Krpm: K e V Bemf A [ V peak to peak] pole pairs 2 2 F Bemf [ Hz] 60 number 1000 Access to rotor

43 How To Measure Bemf 2/2 If you have no access to rotor (e.g. in compressors) follow this procedure: Configure power stage (see later) + - Configure drive parameters for sensor-less as described in slides but Set current ramp initial and final values equal to motor nominal current value Set the speed ramp duration to 5000ms and speed ramp final value to around 50% of maximum application speed Set minimum start-up output speed higher than speed ramp final value Configure control stage Start the motor ramp-up and look with the oscilloscope to the voltage between two motor phases When the driving signal are switched off, rotor was probably moving then look to the B-emf K e V Bemf A [ V peak to peak] pole pairs 2 2 F Bemf [ Hz] 60 number 1000 No Access to rotor

44 Other Electrical Parameters Max rated speed (rpm) Should be provided by motor producer (if not, set it to max application speed) Maximum motor rated speed above which motor can get damaged Maximum application speed must be lower than this value Nominal current (in A, 0-to-peak) Motor rated current, must be provided by motor producer It will be used to limit the imposed motor phase current during normal operation Nominal DC voltage Nominal DC bus voltage from which the motor should run, must be provided by motor producer Demagnetizing current Rotor demagnetizing current, may be provided by motor producer (if not use default value, i.e. motor nominal current) Used to limit the amount of target negative Id during flux weakening

45 Motor Control SDK Workflow 3/4 With Motor Profiler the motor is running but the user can develop his own code! Finalize the MC project using Workbench and use your favorite IDE to develop your code. MC Workbench

46 Create A New WB Project Based On The ST Evaluation Board Choose: New Project

47 Create A New WB Project Based On The ST Evaluation Board Choose: 1. Applications 1

48 Create A New WB Project Based On The ST Evaluation Board Choose: 2 2. Single or dual motor

49 Create A New WB Project Based On The ST Evaluation Board Choose: 3 3. Board approach: Choose if you are using Inverter, MC Kit or Power plus Control boards. Select the board used or create your own custom board.

50 Create A New WB Project Based On The ST Evaluation Board Choose: 4 4. Motor: Choose motor from a motor database. (You can save your motor parameters from your project.)

51 Create A New WB Project Based On An Example Choose the WB example project that best fits your needs. Choose the one with the same name of the ST evaluation board you are using, or choose the one with the same microcontroller you are using.

52 Create A New WB Project Starting from the board selection or example project, the control stage parameters will be populated with the correct values. For a custom project, the user can set all the parameters. STM32303E-EVAL

53 Set Up Power Stage Starting from the board selection or example project, the power stage parameters will be populated with the correct values. For a custom project, the user can set all the parameters.

54 Set Up Drive Parameters Starting from the board selection according to the chosen application, drive parameters will be populated with the correct values. For a custom project, the user can set all the parameters. Applications

55 Parameter Generation Once all the parameters have been entered in the ST MC Workbench, select the output path in the option form and choose SystemDriveParams present in the FW working folder. Click on the Generation button to configure the project.

56 Compile And Program The MCU Run the IAR Embedded Workbench. Open the IAR workspace (located in Project\EWARM) folder according to the microcontroller family (e.g. STM32F10x_Workspace.eww for STM32F1). Select the correct user project from the drop-down menu according to the control stage used (e.g. STM32F10x_UserProject - STM3210B-EVAL). Compile and download. Compile & program Select project

57 Compile And Program The MCU Optionally, run Keil uvision. Open the Keil workspace (located in Project\MDK-ARM) folder according to the microcontroller family (e.g. STM32F10x_Workspace.uvmpw for STM32F1). Select the proper user project from the drop-down menu according to the control stage used (e.g. STM3210B-EVAL). Compile and download. Program Compile Select project

58 Motor Control SDK Workflow 4/4 Finally the user can send commands (e.g. start, stop, execramp, ) via serial communication. Use the Workbench for debugging and real time communication.

59 Arrange the system for running the motor: Connect the control board with the power board using the MC cable. Connect the motor to the power board. Connect the power supply to the power board and turn on the bus. If the board is equipped with the LCD: Press joystick center on Fault Ack button to reset the faults. Press joystick right until the Speed controller page is reached. The press joystick down to reach the Start/Stop button. Press the center of the joystick to run the motor. Run The Motor

60 Optionally you can start the motor using the ST MC Workbench. Connect the PC to the control board with the USB to RS-232 dongle (and a null modem cable). Open the Workbench project used to configure the firmware and click on Monitor button. Select the COM port and click Connect button. This establish the communication with the firmware. To clear the fault, click Fault Ack and then Start Motor button to run the motor. Run The Motor Monitor Connect Select COM port Start Fault ACK

61 State Observer: Startup Procedure The sensorless algorithm is a bemf observer, so the motor should rotate to produce BEMF. That s why a startup procedure is required. Startup needs to be tuned (depend on inertia, load..) Two options of settings: basic and advanced Basic Advanced

62 How To Customize The Sensor-Less Start-Up Set current ramp initial and final values equal to motor nominal current value / 2 (if load is low at low speed, otherwise it can be set up to times nominal current value) Set speed ramp final value to around 30% of maximum application speed According to motor inertia it may be required to increase the speed ramp duration Set minimum start-up output speed to 15% of maximum application speed (if required, decreased it later) Set estimated speed band tolerance lower limit to 93.75% Enable the alignment at the beginning of your development (duration 2000ms, final current ramp value from 0.5 to 1 times motor nominal current according to load) Basic

63 Speed Current Startup Procedure: Basic, Acceleration Current ramp final value Current ramp initial value Current ramp duration time Speed ramp final value Speed ramp duration time

64 Speed Current Startup Procedure: Basic, Current Current ramp final value Current ramp initial value Current ramp duration time Speed ramp final value Speed ramp duration time

65 Speed Current Startup Procedure: Advanced The programmed rev-up sequence is composed by a number of stages; for each stage is possible to define the duration, the final torque reference and the final speed of the virtual sensor. It is possible to define the starting electrical angle. It is possible to set step variation in the current using duration zero. Torque ref. Stage 0 Duration Stage 0 time Final speed Stage 0 Stage 0 Stage 1 Stage 2 time

66 Troubleshooting Problem: SW error fault message appears and the motor do not even try to start Source: the FOC execution rate is too high and computation can not be ended in time Solution: In Drive settings, decrease ratio between PWM frequency and Torque and flux regulator execution rate (e.g. increasing Torque and flux regulator execution rate by one ) Problem: Over-current fault message appears and the motor do not even try to start 1 st possible source: wrong current sensing topology has been selected in power stage current sensing Solution: select right current sensing configuration 2 nd possible source: wrong current sensing parameters Solution: check power stage parameters 3 rd possible source: current regulation loop bandwidth is too high for this HW Solution: in drive parameters drive settings decrease current regulation bandwidth (normally down to 2000 rad/sec for 3shunt topology and 1000 rad/s for single shunt topology) Typical current regulation loop bandwidth max values are 4500 rad/sec for 1 shunt, 9000 rad/sec for 3-shunt

67 Troubleshooting Problem: Motor initially moves but then doesn t rev-up, then fault message Rev-up failure appears Source: typically this happens cause the current provided to the motor is not enough for making it accelerate so fast 1 st possible solution: decrease acceleration rate by increasing Start-up parameters speed ramp duration (being Start-up parameters speed ramp final value set to about 30% of maximum application speed) 2 nd possible solution: increase start-up current by increasing current ramp initial and final values up to motor nominal current Enabling Alignment phase (at least at the beginning of the development) makes start-up more deterministic, use around 2000ms, half of nominal current as first settings Problem: The rotor moves and accelerate following the ramp-up profile but then it stops and the fault message Rev-up failure appears (a mix of following problem sources can be occurring): 1 st possible source: Observer gain G2 is too high and this makes speed reconstruction a bit noisy (never recognized as reliable). A mix of following solutions could be required: 1 st possible solution: decrease observer gain G2 by successive steps: /2, /4, /6, /8 2 nd possible solution: Enlarge Drive parameters Speed/position feedback management variance threshold so as to make rotor locked check less demanding. (up to 80% for PLL and 400% for CORDIC) 2 nd possible source: the window where the reliability of the estimation is checked is too small 1 st possible solution: increase speed ramp final value to around 40% of maximum application speed 2 nd possible solution: decrease minimum start-up output speed to 10% of maximum application speed

68 Problem: The rotor moves and accelerate following the ramp-up profile but then it stops and the fault message Speed feedback appears Use speed ramps: having a target speed gently going from the start-up output speed to the final target will avoid abrupt variations of torque demand that could spoil B-emf estimation A mix of following problem sources can be occurring: 1 st possible source: Observer gain G2 is too high and this makes speed reconstruction a bit noisy (for the selected speed PI gains). A mix of following solutions could be required: 1 st possible solution: decrease observer gain G2 by successive steps: /2, /4, /6, /8 2 nd possible solution: Run motor in torque mode, if trouble doesn t exist in torque mode, it means speed regulator gains are not optimal try changing them 2 nd possible source: frequent situation when the start-up has been validated too early Troubleshooting Solution: Try increasing Start-up parameters consecutive successful start-up output test (normally to not more than 4-5) being minimum start-up output speed set to 15% of maximum application speed (if required, decreased it later) Problem: motor runs but current are not sinusoidal at all 1 st possible source: speed PI gains are not good Solution: decrease Kp gain (and act on Ki evaluating speed regulation over/under shooting during transients)

69 DAC functionality can help to debug and tune the application. Use DAC Channels Enabling Selection with WB Selection with LCD

70 Typical DAC waveforms of tuned system Use DAC Channels Green: phase A motor current Yellow: DAC ch1 (Ia) Pink: DAC ch2 (Ib) Green: phase A motor current Yellow: DAC ch1 (Obs. BEMF Alpha) Pink: DAC ch2 (Obs. BEMF Beta)

71 Thank You!